Telegraphic printing mechanism



Nov. 6, 1934. A. VISCHER, JR

' TELEGRAPHIG PRINTING MECHANISM Filed April 6. 1952 4 Sheets-Sheet l mllllllllllllllll n INVENTOR ATTORNEY Nov. 6, 1934- -A. VISCHER, JR

TELEGRAPHIC PRINTING MECHANI SM Filed April 6, 1932 4 Sheets-Sheet 2 9 6 4. 1L H i M Q s. t? 3 M 2 M km n .3 wN r15 m I ENTOR 7% ATTORNEY Nov. 6, 1934.

A. VISCHER, JR

TELEGRAPHIC PRINTING MECHANISM Filed April 6. 1932 4 Sheets-Sheet 5 FIG].

IN ENToR' F IGB ATTORNEY Nov. 6, 1934. A. VISCHER, JR

' TELEGRAPHIC PRINTING MECHANISM Filed April 6, 1932 4 Sheets-Sheet 4 INWVENTOR Z 7 W ATTORNEY FIGJB.

Patented Nov. 6, 1934 TELEGRAPHIO PRINTING "MECHANISM Alfred Vischer, Jrt, Ridgewood, N..J.. :assignor-to- The Financial Press Companies i of America, Boston, Mass, a trust of Massachusetts Application April6, 1932,-Serial No. 605,614

-16 Claims.

This invention relates to high speedlprinting mechanisms of the type adapted'to' printa series of letters "or other characters across a sheet-or 1 tape Lin rapid succession in response to signals transmittedfrom a remotepoint. 'It;has partic- -ular reference to aiprinter of this character employing a rotatable printing wheel which is shifted across the paper 'at letter-space increments but restored with one quick movement and is rotated continuously inthe same direction und'er control of an escapement to select the characters tobe printed.

it has been asprima'ry vobjectuof the invention ito soconstruct and-arrange the various parts :as to spee'd upthe operation of'sucha printer so that a f considerably greater a number or char- :acters may be printed within a given time interval than has heretofore been. possible. zAmongith'e specific features of theinventio'n by which this object is attained is the provision of so thatiprinting may be ei'iected in a straight line even at high speeds. A. still further'feature is the provision of an improved dash-pot con- .vstruction which permits rapid return of the type wheel carrier, "after a 1 line has been: printed and to positi'on it for .the .printingbf the next line, without rundue vibration i or ejar "upon the parts.

kOther 'features and advantages of the improved construction will be made apparent .from the detailed description of one illustrative embodiment :of the invention which will now be given .in conjunction with the accompanying drawings in which:

Figure l :is ra front, elevational view of the printing wheel driving and shifting mechanism.

Figureiaisca top'planview of thesame.

Figure -3-is a detail view, in elevation, of "the escapement ,pawl with the casing in which it is mounted shown I in section.

=Figure-4 is an enlarged detail View in sectionalong the line i-4: of Figure .3.

Figure 5is a'detail View in section'along the line5--5 of Figure 4.

Figures is an enlarged bottomviewmf the escapementrpawl, as --viewed along the line 66 of Figure 3.

pot construction.

Figure 7 is an enlarged detail .view of the dash pot-construction, largely in vertical section through thesame.

Figure 8 is -a sectional view ii- 8 1 of Figure 7.

Figure- 9 i is a vertical sectional view along the 1ine'-9 #9 of :Fi'gure 1.

Figure -10 is a detail view in vertical section along the line along the line 10-10 of Figure'l.

Figure ll is a detail View iniplanof the dashg5 *F-igure 12 is an enlarged sectional viewthrough the type wheel unit.

FigureslB and Mare detail, sectional views alongthe-lines -1313 and .14--14, respectively, of Figure 12.

F'igure 'l-5 -is a perspective view: of certain parts of "the escapement unit in disassembled relation.

Figure lfi is a'sectional view through the magnet along'theline 1616 of Figure 2. 7.

-Figure l7 is=a perspective view of a carriage return *mechanism, and

Figure 18 is a detail view along the line -l8- l8 of Figure :2.

*Referringno'w to the drawings-there is .pro- 30 vided a main'frame lo of suitable form and cons'truction to support the various operating devices. =A motor 11 is provided to=drivea main shaft 12 which servesasthe driving source for the parts to be actuated. Throughhelical gear- 5 mg -l3 -it*provides the motive power for there-- taticn of the type wheel'supporting shaft 14. A friction elutch '15 -is interposed in the driving connection to the shaft i=4 so that while the shaft 12 is constantly driven so long as the machine isfin operation the shaft 14 may be independently -controlled and arrested in any desired'position. The extent of rotation of the -shaft"1=4 is controlled'by an escapement mechanism including an escapement wheel 16 secured to the shaft. An esca'pement pawl 17 having projections or pallets 18 is adapted to bef oscillated to carry these projections alternately 'into engagement with the teeth of 'the escapement wheel. The pawl 17 iscarried by an armature member :19, which may be regarded as apart ofthe pawlunit-and which is formed of any suitable electro-magnetic'material. The armature may conveniently be formed as a flat stamping from stock, say about'a tenth of an 5 inch inthickness. Any suitable form of connection may 'be :provided between the .pawl and armature. They may, for example, be provided :with interengaging prongs and slots welded or otherwise permanently connected.

The pawl itself is preferably formed of nonmagnetic material so that it will not tend to stick to the teeth of the wheel and will reduce flux leakage. The pallets 18 are preferably made of hardened tool steel or other suitable material.

At each end of the armature there is mounted a supporting member 20 formed of resilient material, preferably tempered spring steel. These members, as will be explained, serve to support the armature from a rigid portion of the machine and are adapted to permit a rapid oscillation of the pawl in response to electrical impulses. It has been found exceedingly difficult to provide a suitable support for the armature which will have the desired restoring action assisting in the rapid swinging of the armature and pawl to the opposite side when the current is reversed and at the same time will stand up under continual use over a long period and at a high speed. As will more clearly appear hereinafter the escapement pawl should be capable of receiving &0 to 60 complete oscillations per second in the transmission of messages at a high speed. To produce these rapid oscillations it is necessary that the armature be placed under a considerable force tending to centralize it, thus offsetting the inertia which would exist in a freely pivoted member. It has been found that the supporting members 20, if not properly applied, tend to work loose from the armature. Furthermore, when they are formed simply as stampings from sheet material it has been found that they very quickly give way to the strains imparted by the rapid oscillations and are soon sheared off. These difficulties have been overcome in the present construction.

In the first place the members 20 have been applied to the armature in an improved manner which tends to obviate working loose at the joints. Each member is provided at its inner end with a slot 21 which serves to divide it into forked portions adapted to straddle the end of the armature. There is also provided a button or disc 22 cut in half after assembly to provide a slot 23 between the upper and lower portions to receive the member 20. This disc is received by a slot 24 cut into the end of the armature, the disc abutting against the inner end of the slot. The parts when assembled are held together by solder. This provides a connection which appears to have sufiicient yield to absorb the strains incident to rapid oscillations. Now to overcome the shearing tendency referred to the members 20 are stamped from a thin rib- Icon of tempered, spring steel in lieu of being stamped from a fiat sheet. In this way the scoring of the edges of the members which invariably results from a stamping operation will be avoided. It has been found that these minute score lines when left in the longitudinal edges of the member will form the starting point of a shear which in the course of a relatively brief period will work entirely across the member. By stamping the members from a narrow; ribbon having just the width of the finished member smooth, rounded edges 25, shown on a magnified scale in Figure 4, may be provided along the longitudinal sides and these edges will be entirely free of score lines. The ribbon of material from which the members are formed may, if desired, be stamped or cut from a wider sheet but before being used to stamp out the parts 20 it should then be passed through suitable operations such as rolling or drawing to make the edges into the smooth, rounded form shown. This will serve to eliminate any scoring that might have been produced in the original cutting or stamping operation. As a result of the construction and mounting of the members 20 in the manner explained the difficulties of breakage and separation previously encountered have been overcome.

For the purpose of suspending the armature the members 20 are provided with openings 26 adapted to receive special nuts kept from turning by square shoulders engaging the sides of the opening and in turn receiving small bolts or screws 27 passed through openings in a casing 28 surrounding the armature and suitably secured to a portion of the machine frame. A spacing collar 29 around each bolt serves to hold the armature in proper position. The armature, as is customary in devices of this character, is mounted between the poles of a permanent magnet 30 at the end of which the casing 28 is carried. Within the casing two laminated pole pieces 31 are so arranged that they serve to extend the poles of the magnet 30 inwardly to planes a short distance on either side of the armature. The ends of the pole pieces are divided to present two like poles on each side of the armature, one above and the other below the pivotal axis of the armature. A coil 32 surrounding the armature and inserted in the recesses between the upper and lower poles of the pole pieces is adapted to receive current impulses in accordance with signals sent out from suitable sending apparatus. These impulses are passed alternately in opposite directions through the coil and thereby temporarily magnetize the armature in one sense upon reception of one impulse and in the opposite sense upon the next impulse, in a manner well known. This reversal of the polarity of the armature causes it to oscillate upon its supports and correspondingly carries the projections 18 of the escapement pawl alternately into and out of mesh with the teeth on wheel 16. This brings about the desired control over the rotation of the shaft 14. It will be understood that, in accordance with the common practice, the shaft 14 is rotated always in the same direction and the escapement is so controlled that the extent of rotation permitted is just suificient to bring the successive characters desired into printing position.

The characters to be printed are carried by a printing wheel 33 slidably mounted upon the shaft 14 but keyed thereto so as to rotate with the shaft. In view of the high speed with which the wheel is rotated from one position to the next, it is preferably formed of very light construction so that there is little inertia to overcome in setting it in motion and arresting it.

It is important that the wheel should be capable of sliding easily along the shaft 14 so that it may be shifted step by step at letter space increments by suitable means, such as that disclosed in detail in my prior Patent No. 1,832,160, granted Wheel 33 1 novogsio a threaded portion at the end of i the sleeve 331 serves-to-hold the wheel in fixedrelation to the sleeve. The shaft 14 is provided with-a keyway 34with which inward extensions of key members 35 and 36'are adapted to cooperate. These key members are carried at opposite sidesof the printing wheel disc and are so constructed as to provide a certain amount of play in the keyway 34; that to say the extensions which enter the keyway are slightly less in thickness than the width of the keyway. This serves to provide the desired easy sliding of the wheel along the shaft. The keyelement 35 is positively clamped to the printing wheel and sleeve by means of the screw cap 333. The relation between the inner end of the element 35-and the wheel 33, therefore, is fixed. The key element 36, on the other hand, is carried loosely upon a hub portion 334 of the sleeve 331 so that a slight relative movement may take place between this key element and the wheel. A spring 39 is connected between atab 40 struck up from a portion of the wheel and an eyelet el carried by the key element 36. The spring 39 thus tends to produce relative rotative movement between the wheel and key element 36. The extent of such movement, however, is limited by the amount of play between the key elements and the keyway 34. The construction is suchthat the inwardly projecting of the element 35 will bear against one wall of the keyway while the inward projection of the element 36 will bear against the oppositewall of the key way. Therefore, while a certain amount of play is permitted between the keys and keyway so as to permit an easy sliding action, the spring 39 will always tendto maintain-the wheel ina definite relation to the grooveyin the shaft. In rapid rotation of the wheel the play in the parts may tend to produce a slight=lag between the wheel and the shaft This lag, however; willbe taken up by the spring 39 when the shaft comes to rest, as well as by the momentum of the wheel itself. Therefore, when the printing takes place a moment later, printing or" *the characters in proper alignment'is insured.

By means of electrical circuits and devices well known'in the art, orby means of the arrangement disclosed in the-copending'application of Herbert L. Paulding, S. N. 603,468 filed April 6, 1932, now Patent Number 1,957,076; May

1, 1934, a printing impulse which results in the when the final impulse of a series is sustained to an appreciably longer duration, and the-wheel has reached its new setting, this reduction in frequency will cause an electro-magnet 42 to be operated to control the operation of a-spring clutch 43. This clutch is released:'by:the-'opera, tion of a detent or disabling pawl 44 secured to a shaft 44]. upon the energization of the electromagnet 42min the manner explained this electromagnet attracting an armature 442 securedto Upon rocking of'the pawl 44, the

shaft 441. clutch 43 and its connected shaft 45 will be released for operation by the drive shaft 12. Suitable helical gearing 46*may be provided between the: shaft 121'and'the left-hand member of the clutch 43 (Fig; l). Rotation of the shaft 45 will bring about the reciprocationof a pair of racks 47, inthe manner more fully explained in my prior patent, before-mentioned. Reciprocation ofthese-racks will serve to shift a carriage 48 at letter space increments along a supporting shaft 49, this being accomplished by the engagement of a pair of pawls 50 with the teeth of the ratchet-toothed. racks 4'7. The pawls 50 are pivotally mounted at 51 upon a portion of the carriage 48. An upwardlyextending portion 52 of the carriage is forked to engage the opposite sides of a grooved portion 53 of the sleeve of the type wheel assembly. At its lower end the main frame of the carriage 48 is provided with a bearing 54- slidable along the shaft 45. This serves to position and guide the carriage in such a way that the prongs 52 will not bear against thebottom of the groove in the. portion 53 of the type wheel unit and will consequently not interfere with the free rotation of the type wheel. It will be apparent, however, that through the connections explained the step-by-step movement of the carriage 48 will produce a corresponding shifting of the type wheel along its supporting shaft 14. It may be mentioned that rotation of the shaft 45 will bring about the operation of a printing platen, in a manner known in the art. Inasmuch as the operation of the platen forms no part of the present invention, however, this part of the mechanism has not been disclosed herein.

After a series of characters has been printed across a sheetof paper, (not shown) which is suitably supported in printing relation to the wheel33, the wheel and the carriage 48 will be restored to the left-hand side of themachine (Fig.1 and 2) and the paper will be line-spaced so that the printing of the next line across the sheet may be brought about. The return of the carriage for this purpose is produced by means of a spring 55 (Fig; 1'7) connected at one end to astud 56 carried by a portion of the frame and connected at its opposite end to a lever 5'7. This lever at its upper end is connected to the carriage by means of the stud 51 and at its lower end is pivotally mounted on a frame 58 which-in turn is pivotally mounted at 59 on a portion of the frame of the machine. tion of the spring 55, lever 57, and frame 58 is such thatthe force tending to restore the carriage' to the left-hand side of the machine is substantially constant at all times. In order to permit the spring 55 to function, it is necessary to lift the pawls 50 out of engagement with the racks 4'7. This is accomplished by means of an arm 60 (Fig. 18) carried by a sleeve 601 shiftable with-the carriage assembly 48 but rockable with relation to the carriage. provided with an inwardly extending key portion adapted to ride in a groove or keyway 61 provided in the shaft 49. While the carriage 48 is simply slidable longitudinally with the shaft, the arm 60 partakes of this longitudinal move- The rela- The arm 60 is ment and is also rocked with the shaft, when the latterisrocked by means to be later explained.

Leaf) pawls from the racks. This allows the spring to return the carriage and the printing wheel toward the left. (Figs. 1 and 2).

Rocking of the shaft 49 (Figs. 9 and 10) to disengage the pawls so in the manner explained is accomplished in th following manner: Upon the shaft 45 there is mounted a cam member having a projection 64 adapted upon each rotation of the shaft 45 to engage the lower end of a two-armed floating lever 65. This lever is pivotally connected at 66 with a plate 67 secured to the shaft 49. Normally the rocking of the lever (-35 will be an idle movement about the pivot 66. However, when it is desired to return the carriage to the left of the machine, the upper end of the lever is held against inward movement by means of a projection 68 carried by the printing wheel shaft 14. The projection 68 corresponds with a blank position on the printing wheel,-that is to say whenever the blank space on the printin wheel is brought opposite the printing platen, the projection 68 will be brought in line with the end of a member 69 pivotally mounted at the upper end of the two-armed member 65. It will be apparent that under these conditions rocking of the member 65 by means of the projection 64 will cause the pivot 66 of the member to be shifted toward the right in Fig. 9. This will produce a rocking of the plate 6'7 and shaft 49. This in turn will cause the pawls 5G to be disengaged from the racks and will bring about the return of the carriage in the manner explained. A tension spring '70 serves to hold the member 69 in the position shown with relation to the two-armed member 65 and also serves to hold the lower end of member o5 against the bottom of cam 64:. Clockwise movement of the member 69 (Fig. 9) upon the member 65 is permitted, if required, to prevent blocking of the parts.

In order to cushion the return of the carriage to the left of the machine, an improved form of;

adjustable dash-pot is provided. (See Figs. 1, 2, 7, 8 and 11.) This includes a piston portion '71 rigidly secured to the frame of the carriage unit 48. The piston is adapted to enter a cylinder 72 integral with or otherwise carried by a sleeve 73 secured to the shaft 49. By securing the cylinder to the shaft in this way concentricity is insured between the cylinder and piston. The one being secured to the shaft and the other slidable thereon a definite alinement is maintained. This is important inasmuch as the clearance between these relatively moving parts is very small. If an attempt were made to secure the cylinder to the frame member through which the sleeve '78 passes it would be difficult if not impossible to maintain ccncentricity between the cylinder and piston. The cylinder '72 is preferably formed of brass or similar resilient material which at the same time is capable of being readily compressed. At its outer or righthand end (Fig. 7,) the wall of the cylinder is considerably reduced, having a thickness of only about two hundredths of an inch. A steel band 74 is mounted around the outer end of the cylinder. This band is split and the two ends are brought together along a diagonal line 75, or a plane at an angle to the axis of the cylinder. (Fig. 8.) By means of a screw '76, the ends of the band may be brought more closely together or permitted to separate, as desired. Upon bringing the ends of the band together, the material of the cylinder will be compressed so that its circumference or inside diameter will be correspondingly reduced. In this way the air gap between the outer surface of the piston '71 and the inner wall of the cylinder may be varied to produce the desired cushioning effect. By arranging the ends of the steel band on a diagonal line 75, as shown, the danger of causing the wall of the cylinder to buckle into the gap between the ends of the band will be avoided. Due to the resilience of the material of the cylinder it will expand again if the screw 76 is turned to free the grip of the band '74. By means of the improved construction there is, therefore, provided an adjustable dashpot action or cushioning effect between a non-rotatable piston secured to the sliding carriage and a rotatable or rockable cylinder carried by the shaft along which the carriage slides.

The operations of the various portions of the machine have been explained in connection with the detailed description. Repetition at this point is believed to be unnecessary. -t should be observed, however, that the various improvements incorporated in the mechanism in accordance with the present invention all contribute to the speeding up of the operation as a whole. The improved mounting of the escapement pawl makes it possible to oscillate the pawl and armature unit more rapidly than has heretofore been possible, without danger of loosening or breaking the parts. more rapid turning of the printing wheel from one character to the next. The improved construction and mounting of the printing wheel assembly permits it to be more readily shifted at letter space increments and permits rapid rotation of the wheel for character selection without danger of misalinement of the printed characters. So also a more rapid return of the carriage upon completion of a line is made possible by the improved da-shpot construction without danger of injury to the parts.

While various features of the construction have been disclosed in considerable detail in relation to a particular type of printing mechanism, it will be understood that certain of these features may be considerably modified and may be used in other relations without departing from the general principles and scope of the invention as defined by the claims.

I claim:

1. In a telegraphic printer 2. character wheel, a supporting shaft therefor, said shaft having a keyway therein, a key rigidly secured to said wheel and adapted to enter said keyway, a second key movably mounted on said wheel and adapted to enter said keyway, and resilient means tending to shift said second key relative to said wheel.

2. In a telegraphic printer a character wheel, a supporting shaft therefor, said shaft having a keyway therein, a key rigidly secured to said wheel and adapted to enter said keyway, a second key movably mounted on said wheel and adapted to enter said keyway, and means for holding one of said keys against one side of This enables said keyway and the other y against the opposite side of the keyway.

3. In a telegraphic printer a character wheel, a supporting shaft therefor, said shaft having a keyway therein, a pair of keys carried by said te'r wheel unit slidably mounted on said shaft, interengaging means on said unit and shaft for enforcing rotation in unison, said means permitting a slight play, means angularly movable upon said unit and interengaging with said shaft for rotation therewith, said last mentioned means being constrained for movement with said unit along the shaft, and tensioning means tending to produce angular movement of said second mentioned means relative to said unit.

5. In a telegraphic printer a shaft having a keyway, a sleeve slidably mounted on said shaft, a character printing wheel mounted on said sleeve, means for clamping said wheel on said sleeve, a key interposed between said clamping means and wheel, said key having a slight play in said keyway, a key angularly adjustable on said sleeve and having a similar play in said keyway, and a spring tending to produce angular movement of said second mentioned key on said sleeve.

6. In a device of the class described a shaft, a carriage slidable on said shaft, spring means for shifting the carriage in one direction, and a dash-pot for cushioning the movement of said carriage by the spring means, said dash-pot comprising a part secured to said shaft and coaxial therewith, and a part slidable alongsaid shaft with the carriage and co-axial with said shaft. I

7. In a device of the class described a shaft, a carriage slidable on said shaft, means for shifting said carriage step by step in one direction and retaining the carriage in shifted position, means for returning the carriage when released, means for rocking the shaft, means for releasing the carriage upon rocking the shaft, and a dash-pot including a part on the carriage surrounding the shaft and co-axial therewith and a part fixed to the shaft and co-axial therewith, said parts being carried into and out of telescoping relation for cushioning the return of the carriage.

8. In a device of the class described a shaft, a carriage slidable on said shaft, means for shifting said carriage step by step in one direction and retaining the carriage in shifted position, means for returning the carriage when re leased, means for rocking the shaft, means shiftable with the carriage but rockable relative thereto upon rocking of said shaft for releasing the carriage, and a dash-pot including a part rockable with the shaft and a part held against rocking for cushioning the return of said carriage, said parts being carried into and out of telescoping relation.

9. In a device of the class described a dashpot comprising a piston and a cylinder mounted on relatively movable parts, said piston entering freely into said cylinder, and adjustable means for reducing the circumference of the cylinder to vary the cushioning effect.

10. In a device of the class described a dashpot comprising a piston and a cylinder movable into and out of cooperation, said cylinder being formed of resilient, readily compressible material, and adjustable means for compressing a portion of said cylinder to vary the circumference thereof.

11. In a device of the class described a dashpot comprising a piston and a cylinder movable into and out of cooperation, said cylinder being formed of resilient, readily compressible material, and a split band surrounding a portion of said cylinder and adapted to compress the same to vary the circumference of said portion.

12. In a device of the class described a dashpot comprising a piston and a cylinder movable into and out of cooperation, said cylinder being formed of resilient, readily compressible material, and a split band surrounding a portion of said cylinder and adapted to compress the same to vary the circumference of said portion, said band being split along a plane at an angle to the axis of the cylinder.

13. In a device of the class described a dashpot comprising a piston and a cylinder movable into and out of cooperation, said cylinder beingformed of brass, a steel, split band surrounding a portion of said cylinder, and means for contracting said band to compress said portion of the cylinder and vary its circumference.

14. In a device of the class described a dashpot comprising a piston and a cylinder movable into and out of cooperation, said piston and cylinder being rotatable relative to each other, and means for varying and setting the clearance between said piston and cylinder to regulate the dash-pot.

15. In a device of the class described a dashpot comprising a piston and a cylinder movable into and out of cooperation, the inside dimensions of said cylinder being slightly larger than the outside dimensions of the piston, one of said parts being formed of resilient material, and means for varying and setting the dimensions of said one part to vary the clearance between the parts.

16. In a device of the class described a shaft, a carriage slidably mounted on said shaft means for shifting said carriage to a predetermined position, and means for cushioning the carriage as it reaches said position, comprising a cylinder and a piston both surrounding said shaft and adapted to be moved into and out of telescoping relation, one being secured to said shaft and the other mounted thereon and slidable with said carriage.

ALFRED VISCI-IER, JR. 

